Plasma apolipoprotein (a) is increased in Type 2 (non-insulin-dependent) diabetic patients with microalbuminuria

Abstract

Patients with Type 2 (non-insulin-dependent) diabetes mellitus complicated by microalbuminuria or albuminuria, have an increased risk of developing macrovascular disease and of early mortality. Because lipoprotein abnormalities have been associated with diabetic nephropathy, this study tested the hypothesis that levels of apolipoprotein (a) are elevated in patients with Type 2 diabetes and increased levels of urinary albumin loss. Levels of apolipoprotein (a) in diabetic patients with microalbuminuria (n = 26, geometric mean 195 U/l, 95% confidence interval 117-324) and albuminuria (n = 19, 281 U/l, 165-479) were higher than in non-diabetic control subjects (n = 140, 107 U/l, 85-134, p < 0.05), and in the albuminuric group than diabetic patients without urinary albumin loss (n = 58, 114 U/l, 76-169, p < 0.05). Patients with microalbuminuria and albuminuria had levels comparable with patients undergoing elective coronary artery graft surgery (n = 40, 193 U/l, 126-298). Apolipoprotein (a) levels were higher in diabetic patients with macrovascular disease than in those without (n = 49, 209 U/l, 143-306 vs n = 54, 116 U/l, 78-173, p < 0.05). These preliminary results suggest that raised apolipoprotein (a) levels of Type 2 diabetic patients with microalbuminuria and albuminuria may contribute to their propensity to macrovascular disease and early mortality.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

“…Many studies have confirmed ethnic differences in Lp(a) levels where subjects of African descent have about twice as high levels as Caucasians, Hispanics, and many the literature regarding the role of Lp(a) in diabetes mel litus, while some studies found no impact of diabetes mel litus on Lp(a) concentrations, others reported an elevation or a decrease of Lp(a) concentrations. Early studies re ported elevated Lp(a) concentrations in patients with type 1 diabetes mellitus (IDDM) (225)(226)(227)(228)(229)(230), as well as in pa tients with type 2 diabetes mellitus (NIDDM) (231,232). Furthermore, some recent studies in Asian populations report an association between an elevated Lp(a) concen tration and incident NIDDM (233)(234)(235).…”

Insulin and 2-Hour Glucose Levels Are Inversely Related to Lp(a) Concentrations Controlled for LPA Genotype

“…Other studies have relied on large numbers to determine whether NIDDM was related to Lp(a) concentration. Perhaps as a result of inability to correct for the large variation due to LPA genotype, however, there has been considerable variation in conclusions, with some studies reporting higher Lp(a) levels 37 and some lower, 3 while most have found no significant effect. 38,39 In the current study, we found that diabetic subjects had lower residual Lp(a) concentrations than nondiabetic subjects, but this difference was not significant.…”

Association of elevated lipoprotein(a) levels and coronary heart disease in NIDDM patients. Relationship with apolipoprotein(a) phenotypes

“…Given this restriction, no correlation was observed between albuminuria and Lp(a) concentrations. Data on the possible association between these two variables are inconclusive in NIDDM, as both positive [33] and negative findings have been reported [34,35].…”